Magnetic flow detector system with marking fluid applicator operable by variable pressure of a control fluid

Claim 1

A FLAW MARKING SYSTEM FOR MARKING FLAWS DETECTED IN A LONGITUDINALLY MOVING WORKPIECE, THE SYSTEM COMPRISING: (A) A MARKING FLUID APPLICATOR CONNECTED TO RECEIVE A MARKING FLUID AND A REGULATING FLUID AND RELEASE SAID MARKING FLUID ONTO SAID WORKPIECE IN RESPONSE TO VARIATION IN PRESSURE OF SAID REGULATING FLUID PROVIDED TO SAID APPLICATOR; (B) A SOLENOID FOR CONTROLLING SAID PRESSURE OF SAID REGULATING FLUID PROVIDED TO SAID APPLICATOR; (C) A TRANSISTOR HAVING BASE, EMITTER, AND COLLECTOR ELEMENTS, THE SOLENOID AND A POWER SOURCE BEING CONNECTED IN SERIES WITH THE EMITTER AND COLLECTOR ELEMENTS; (D) A RESISTANCE CONNECTED IN SERIES WITH SAID SOLENOID; (E) INITIATING CIRCUIT MEANS NORMALLY BIASING THE EMITTER-BASE CIRCUIT OF SAID TRANSISTOR TO RENDER SAID TRANSISTOR IN A NORMALLY-UNSATURATED STATE, SAID INITIATING CIRCUIT MEANS BEING RESPONSIVE TO A CONTROL PULSE TO CAUSE SAID TRANSISTOR TO SATURATE AND EFFECTIVELY CLOSE ITS EMITTER-COLLECTOR CIRCUIT;